Apparatus for forming material using a skew-rolling mill

ABSTRACT

In order to avoid the slight spiral marking on the final section produced by forming material in a skew-rolling mill, and in order to provide exact sizing and shaping of such material, the rolled material leaving the skew-rolling mill is fed through an extrusion die by axial thrust imparted to the material in the skew-rolling mill.

United States Patent [191 Biswas et al.

14 1 Sept. 30, 1975 APPARATUS FOR FORMING MATERIAL USING A SKEW-ROLLING MILL [75] Inventors: Amit Kumar Biswas, Kaarst; Hugo Feldmann, Hongen; Friedrich Wilhelm Hollmann. Neuss-Rusehenberg; Erich Bretschneider, Buderich. all of Gernrgmy [73] Assignee: Schloemann-Siemag Aktiengesellschaft. Dusseldorf, Germany 221 Filed: Sept. 17, 1974 211 App]. No.1 507.140

[30] Foreign Application Priority Data Sept. 19. 1973 Germany ..234 7023 [52] US. Cl 72/68; 72/78 [51] Int. Cl.'- B21B 15/00 [58] Field of Search 72/68. 77, 78. 100, 206

[56] References Cited UNITED STATES PATENTS 2.032.917 3/l936 Cushwa 72/78 2.333.238 11/1943 Finnie 3.132.545 5/1964 Arata 3.735.617 5/1973 Bretschneider 72/78 Primary E.\'aminerLowell A. Larson Attorney, Agent. or FirmHolman & Stern [57] ABSTRACT In order to avoid the slight spiral marking on the final section produced by forming material in a skew-rolling mill. and in order to provide exact sizing and shaping of such material. the rolled material leaving the skewrolling mill is fed through an extrusion die by axial thrust imparted to the material in the skew-rolling mill.

4 Claims, 3 Drawing Figures US. Patent Sept. 30,1975 Sheet 1 of3 Sheet 2 of 3 3,908,420

US. Patent Sept. 30,1975

US. Patent Sept. 30,1975 Sheet 3 of3 3,908,420

APPARATUS FOR FORMING MATERIAL USING A SKEW-ROLLING MILL BACKGROUND OF THE INVENTION The use of skew-rolling mills for reduction of cast slabs or billets is known. This rolling process produces a large change in the cross-sectional size of the material, but also leaves the surface of the material with'a slight spiral marking on the final section.

THE INVENTION According to this invention, there is provided a process for forming material using a skew-rolling mill, wherein the rolled material leaving the mill is fed through an extrusion die, by axial thrust imparted to the material in the mill. The die thus lies in the path of the rolled material leaving the mill. i

An advantage of the invention is that material can be produced with any desired cross-sectional shape or profile, with exact sizing and with an acceptable surface finish, from a continuously cast slab, or from another type of cast billet.

Preferably, the die merely provides a cleaning function for the rolled material. In this manner, deformation of the starting material to form the required crosssectional shape is done by the skew-rolling mill, and the die provides only a relatively small further deformation to clean up the material.

The process of the invention combines the advantages of a skew-rolling mill with those of an extrusion press. The rolling mill changes the cross-section of the starting material to the required shape, and also imparts to the rolled material an axial thrust which passes it through the die.

In normal extrusion presses for extruding metal, about 50% of the press power is used in overcoming the friction load. Also, during the extrusion process, both the macrostructure of the billet must be changed and the shaping of the cross-section of material must be carried out by the die.

Using the process of the invention, a material with the required outer surface or cross-sectional shape can be formed and manufactured continuously in an essentially more economical manner than is possible with an extrusion press alone. There is also no longer any limit to the ingot length which can be formed using the process of the invention. Since only relatively low thrust forces are necessary for overcoming friction and providing deformation in the die, the ram or billet pushing device of an extrusion press is omitted.

Preferably, the temperature of the rolled material leaving the mill is controlled before it enters the die, to ensure that it is at a suitable temperature for forming in the die. The optimum temperature of the material for the die-forming or extrusion operation can be achieved by using a suitable automatic temperature control in the rolling mill which controls the'temperature at the end of rolling, and in this way the temperature can be deliberately reduced to a suitable value for the die, by cooling the material in the mill or allowing it to cool to a suitable degree. The die is highly desirable directly adjacent the rolling mill. Any possible kinking of the rolling section is thereby avoided.

It is especially advantageous if a so-called planetary skew-rolling mill is used. This has at least three conical working rolls directed towards each other and the rolling axis, with their axes skewed with respect to the rolling axis. The working rolls are arranged in a roll carrier, and the working rolls relate in the roll carrier and the roll carrier rotates about the rolling axis so that a thrust is imparted to the rolled section by the working rolls without any twisting of the section (see German Offenlegungsschrift No. 1 602 153). The working rolls, and the roll carrier itself, can each have a separate drive for driving them.

In one embodiment of the invention, the die has a die entry opening whose outer shape corresponds to the conical space surrounded by the inclined faces of the working rolls as they rotate. In this way, there is practically no empty space between the exit from the working rolls and the die.

To provide suitable lubrication for the rolled material passing through the die, an annular nozzle or array of nozzles for continuously feeding lubricant into the die may be provided around the die entry opening. If necessary, a suitable cooling medium can be fed through these nozzles. I

If there is too much scale on the surface of the rolled material, a peeling device for the rolled material can be provided just before the entry opening to the die.

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF oNE-E EoDIMENT OF THE INvENTIoN A skew-rolling mill 2 is arranged on a base 1. The drive of the mill is not shown. A roll-carrier 3 is horizontally supported in a housing 4, and is journalled to rotate about a horizontal rollingaxis and about the material 5 being rolled.

At one face of the roll carrier}, at least three opposed and offset working rolls 6 are arranged. Each working roll 6 is journalled in a working roll housing 7 and the housing 7 is adjustable towards and away from the rolling axis. The work rolls 6 are conical in form and in this case have their axes skewed with respect to the rolling axis, i.e., their axes are at an angle to the rolling axis and do not intersect the rolling axis, being slightly spaced therefrom at their shortest distance apart, so that the material 5 is thrust through the rolls (to the right in FIG. 1). Because of this slight inclination, the axes of the rolls do not meet at a point. As the working rolls 6, the working roll housing 7 and the roll carrier 3 rotate about the material 5, the working rolls 6 roll about the material in such a manner that they create a thrust in the course of reduction without allowing the rolled material to twist. To avoid this twisting, the roll carrier 3 and the working rolls 6 have separate drives which can be individually adjusted. Materials of various diameters can therefore be rolled by altering the speed of the working rolls 6 in relation to the speed of the roll carrier 3 and by suitable adjustment of the working rolls 6.

The working rolls 6 are driven by a planetary drive which is not shown. A removable protection cover 8 covers the working rolls 6.

Details of the construction and operation of this planetary skew-rolling mill can be found in German Offenlegungsschrift No. l 602 153, referred to above.

A die 9, arranged in the space generated by the rotation of the conical working rolls 6 about the material 5, has an entry opening 10 on the side facing the working rolls 6. The die 9 is so close to the working rolls 6 that there is practically no empty space. Thus, the material passes directly from the working rolls 6 to the entry opening 10 in the die, and there is no possibility of the material kinking.

The die 9 is arranged in a die holder or bolster 11 which is itself supported in an outlet guide 12. The die holder 11 is secured to the outlet guide 12 by screws or bolts 13.

The outlet guide 12 is journalled in a housing 14 which is axially movable and can be locked. The housing 14 is mounted in a bearing block 15 which in turn is mounted on the base 1.

To ensure continuous lubrication of the section passing through the die, an annular duct 16 with an annular array of nozzle openings 17 is secured to the die 9 around the entry opening 10. Lubricant is fed to the nozzles17 through another duct 18 which is shown in the plane of the drawing, but which is practice will be in another plane, for example at 45 to the plane of the drawing. The duct 16 is secured to the die body by bolts 19 in bores 20.

A conventional peeling device (not shown) can be provided immediately in front of the die entry opening 10, to remove unwanted scale from the surface of the 7 rolled material.

There is a conventional temperature control system (not shown) for controlling the temperature of the rolled material 5 as it enters the die 9. In a conventional manner, the temperature control system has a temperature sensor in the mill 2 and by suitable compensation for the changes of temperature which occur in the mill itself, this sensor can control the temperature of the rolled material 5 at the exit from the mill.

We claim:

1. Apparatus for forming material, comprising a skew-rolling mill for rolling said material to form rolled material and impart an axial thrust thereto, said mill having an exit, and an extrusion die immediately adjacent said exit and in the path of said rolled material whereby said rolled material is fed through said die by said axial thrust, said working rolls having inclined faces which surround a conical space as said working rolls rotate during the operation of said mill, and wherein said die has an outer shape corresponding to said conical space.

2. The apparatus of claim 1, and further comprising an annular duct around the entry opening to said die, said annular duct defining nozzle openings for the passage of lubricant onto said rolled material.

3. The apparatus of claim 1, wherein said mill is a planetary skew-rolling mill and comprises a rotary roll carrier, means mounting said roll carrier for rotation about said material, at least three conical working rolls, means rotatably mounting said working rolls in said roll carrier for rotation with respect to said roll carrier about respective axes of said rolls, with said axes directed towards each other and to the rolling axis of said mill, and skewed with respect to said rolling axis, drive means for rotating said working rolls with respect to said roll carrier, and separate drive means for rotating said roll carrier about said rolling axis.

4. The apparatus of claim 3, and further comprising an annular duct around the entry opening to said die, said annular duct defining nozzle openings for the passage of lubricant onto said rolled material. 

1. Apparatus for forming material, comprising a skew-rolling mill for rolling said material to form rolled material and impart an axial thrust thereto, said mill having an exit, and an extrusion die immediately adjacent said exit and in the path of said rolled material whereby said rolled material is fed through said die by said axial thrust, said working rolls having inclined faces which surround a conical space as said working rolls rotate during the operation of said mill, and wherein said die has an outer shape corresponding to said conical space.
 2. The apparatus of claim 1, and further comprising an annular duct around the entry opening to said die, said annular duct defining nozzle openings for the passage of lubricant onto said rolled material.
 3. The apparatus of claim 1, wherein said mill is a planetary skew-rolling mill and comprises a rotary roll carrier, means mounting said roll carrier for rotation about said material, at least three conical working rolls, means rotatably mounting said working rolls in said roll carrier for rotation with respect to said roll carrier about respective axes of said rolls, with said axes directed towards each other and to the rolling axis of said mill, and skewed with respect to said rolling axis, drive means for rotating said working rolls with respect to said roll carrier, and separate drive means for rotating said roll carrier about said rolling axis.
 4. The apparatus of claim 3, and further comprising an annular duct around the entry opening to said die, said annular duct defining nozzle openings for the passage of lubricant onto said rolled material. 